The engine immobiliser system is designed to prevent the vehicle from being stolen. This system uses a transponder key ecu that stores the key codes of authorized ignition keys. If an attempt is made to start the engine using an unauthorized key, the ecu sends a signal to the ecm to prohibit fuel delivery and ignition, effectively disabling the engine.

The transponder key coil receives this signal, the transponder key amplifier amplifies it, and then the signal is transmitted to the ecu. The ecu matches the key's id code with the vehicle's id code, which was previously registered in the ecu and then communicates the results to the ecm using sfi communication.
Engine immobiliser system
How to proceed with troubleshootingSide doors
The vehicle can be locked
and unlocked using the
entry function, wireless
remote control, door lock
switches, key or inside lock
buttons.
Unlocking and locking the
doors from the outside
â– Using the entry function
(vehicles with smart key
system)
Carry the electronic key to
enable this function.
...
Evaporator temperatur sensor
Removal
Remove air conditioning unit
Remove the air conditioning radiator (see page ac-
185).
Remove evaporator temperature sensor
(see page ac-193)
Inspection
Inspect evaporator temperature sensor
Measure the resistance of the sensor.
Standard resistance
No ...
Data list / active test
Active test
Hint:
Performing the intelligent tester active test allows
relay, vsv, actuator and other items to be operated
without removing any parts. Performing the active
test early in troubleshooting is one way to save time.
The data list can be displayed during the active
test.
...